The invention relates to laser excitation lamps having a discharge tube and a hot pin-shaped cathode. The invention further relates to use of such a lamp as a pumping light source for lasers, and to the production of such lamps.
The present invention is similar to a high-power discharge lamp or pumping light source with pin-shaped cathode in older types of laser devices. The modified laser lamp comprises a so-called pin cathode, which has the shape of a rod and does not have a pointed end. Such laser lamps are known from German patent document DE 102 08 585 (counterpart of U.S. patent application Pub. No. 2003/0161377 A1, the disclosure of which is incorporated herein by reference). These lamps have a longer service life in comparison with standard lamps having cathodes with pointed ends. The pin cathode of this lamp is essentially only cooled by radiant cooling and thus can be hot. From U.S. Pub. No. 2003/0161377 A1 lamps with a pin electrode are known, for which the cathode does not have a pointed shape and which have no emitter material. In addition, around the cathode, i.e., between the cathode and the discharge tube, there is considerable space.
Such lamps are used in high-power solid-state lasers (HPSSL). These include lasers in which a laser crystal is used as the lasing medium. The crystal can have any arbitrary shape, but disk-shaped or rod-shaped configurations are typical.
In older types of laser devices, the starting process represents a serious problem, because the controls of these older types of laser devices cannot reliably control the starting process. Even though such laser devices could be modified at great expense, typically standard lamps with short service lives were used, so that the laser control could reliably control the laser device and extensive investment could be avoided. Standard-type lamps have a pointed cathode, which reaches the full diameter of the discharge tube within a region of a few millimeters behind the tip.
The present invention presents the object of solving the problems arising in the starting process of older types of laser devices for new high-power laser lamps having a pin cathode and therefore a longer service life.
In particular, the present invention presents the object of providing a laser excitation lamp or pumping light source, whose response in the starting process is more reliable in comparison with the prior state of the art.